Current Status and Trends in the Development of the Global Coal Chemical Industry

Thread Content

Modern coal chemical engineering refers to the use of advanced modern technologies to fully exploit and utilize the advantages of coal’s inherent properties, enabling deep processing and comprehensive utilization of coal in order to achieve efficient and clean conversion of coal. It also involves the large-scale production of coal chemical products that can compensate for and replace scarce oil and gas resources. Entering the 21st century, rising oil prices, shortages of petroleum raw materials, and high costs have driven coal conversion technologies into a new phase of development. The advancement and industrialization of petroleum alternative technologies such as large-scale gasification techniques, large-scale methanol synthesis technologies, methanol-to-olefins processes, and synthetic oils have accelerated, pushing the global coal chemical industry into a completely new stage. 　　I. The Development History of the World’s Coal Chemical Industry After the Industrial Revolution, coal was utilized as a raw material for the chemical industry, and gradually an independent coal chemical industry sector was established. The development of the global coal chemical industry has gone through four stages: (1) The primary stage (1776–1930). The primary stage of coal chemistry originated with the Industrial Revolution and was the longest-lasting phase in the history of the development of this industry. During this period, the world’s steel industry developed rapidly, driving continuous innovation and improvement in coking technologies (including semi-coke), coke gasification, by-product recovery, and comprehensive utilization techniques. 　　(II) Period of Comprehensive Development (1930–1945) This period was also when coal-to-oil technology was developed and industrial production began. On the eve of and during World War II, Germany carried out extensive research on coal-to-oil conversion as well as industrial-scale production in order to launch and sustain **. In 1931, direct liquefaction technology was successful, and by 1944, the total production capacity for coal-to-oil conversion reached 4.23 million tons per year ； In 1933, indirect liquefaction technology (F-T synthesis) was put into industrial use, and coal-to-oil production reached 590,000 tons in 1938. 　　While developing direct and indirect liquefaction technologies, Germany also built large-scale low-temperature retorting facilities. After gasification, semi-coke is used in F-T synthesis to produce liquid fuels; low-temperature tar, after simple treatment, is used as fuel for naval ships, or it is subjected to high-pressure hydrogenation to produce gasoline and diesel. Towards the end of World War II, Germany’s production capacity for coal-based liquid fuels reached 4.8 million tons per year; at the same time, various aromatic and heterocyclic organic compounds were extracted from coal tar, which were used as raw materials for dyes and other products. 　　(III) The Depression Period (1945–1980) After World War II, thanks to the large-scale extraction of cheap oil and natural gas, the West was the first to complete the shift in the raw materials used in the organic chemistry industry from coal to oil and natural gas. Industrial coal-based oil production was temporarily halted; only the coking industry continued to develop alongside the growth of the steel industry. This marked the official entry of the world into the era of petrochemicals. 　　Due to South Africa’s unique geographical location as well as its **environmental and resource conditions, the coal-based liquid fuel industry has been developing. In 1955, the industrial plant for the SASOL-Ⅰ Fischer-Tropsch synthesis process was built. In 1977, large-scale fluidized-bed reactors were developed, followed by the creation of SASOL-Ⅱ and SASOL-Ⅲ. In 1982, two coal-to-oil plants with a capacity of 1.6 million tons per year each were built. 　　(IV) Technology development period (1980 to the present) In 1973, the events in the Middle East and the subsequent \"oil crisis\" had a significant impact on the development of the world’s petrochemical industry due to the sharp rise in oil prices, which led to a renewed interest in methods for producing liquid fuels and chemicals from coal. Especially since the 1990s, with severe fluctuations in international oil prices, countries have accelerated research and development in the chemical industry using coal as a raw material, developing a range of strategic reserve technologies in areas such as coal gasification, coal liquefaction, and C1 chemistry. Entering the 21st century, rising oil prices, shortages of petroleum raw materials, and high costs have driven coal conversion technologies into a new phase of development. The advancement and industrialization of petroleum alternative technologies such as large-scale gasification techniques, large-scale methanol synthesis technologies, methanol-to-olefins processes, and synthetic oils have accelerated, pushing the global coal chemical industry into a completely new stage. 　　II. Current Development Status of the World’s Modern Coal Chemical Industry At present, the development of the world’s modern coal chemical industry is primarily concentrated in South Africa (coal-to-oil), the United States (coal-to-methane gas), and China. In 2008, global production of coal-to-oil was approximately 7 million tons, while coal-to-methane gas production was around 1.4 billion cubic meters. These figures accounted for only 0.58% and 0.05% of the world’s total diesel and natural gas consumption respectively, representing a small proportion. 　　South Africa is the most representative country in the world for the development of modern coal chemical industry; it possesses advanced coal chemical technologies and carries out industrial production using them. SASOL is the only company in the world to possess a coal liquefaction plant and to have commercial F-T synthesis technology. At present, the company’s 3 coal-based liquefaction plants consume 45.9 million tons of coal per year. Their main products include gasoline, diesel, wax, gas, ammonia, ethylene, propylene, polymers, alcohols, aldehydes, and a total of 113 other substances, with an overall production volume of 7.6 million tons (production facilities are located in Sasolburg and Secunda). Oil products account for around 60% of this output, meeting 28% of South Africa’s demand for gasoline and diesel. The SAS fixed-bed liquefaction reactor owned by the company is the largest F-T synthesis reactor to date; it has a diameter of 10.7 meters and a height of 28 meters, with a production capacity of 2,500 tons per day per unit. 　　After more than 70 years of development, coal liquefaction technology in South Africa has become highly mature, and the products derived from this technology are now used across the entire chemical industry. Currently, South Africa can not only produce conventional petroleum products such as gasoline, diesel, and kerosene from coal, but also manufacture high-quality petroleum products like aviation fuel and lubricants on a large scale. 　　The Great Plains Synthesis Fuel Plant (GPSP) is currently the only commercial plant in the world that operates on a large scale to produce methane gas from coal. GPSP was established between the first and second oil crises, with the goal of helping the United States achieve its energy independence plan; it has gone through various fluctuations in energy prices as well as changes in ownership throughout that period ； Despite the impact, it continued to operate stably, actively developed new downstream products, and for the first time used CO2 to accelerate oil production, achieving excellent economic benefits. 　　III. Characteristics and Development Trends of the Modern Coal Chemical Industry The modern coal chemical industry is an emerging sector that will still have significant room for growth in the coming period. Generally speaking, modern coal chemical industry has three main characteristics: First, it requires a high degree of \"scaling up, large-scale operation, integration, and establishment of specialized bases,\" with substantial investment levels involved. Unlike the traditional coal chemical industry, modern coal chemical production operates on a larger scale; the annual production volume for coal-based methanol, coal-based dimethyl ether, and coal-based oil already exceeds 1 million tons, while the scale for coal-based olefins is required to be between 500,000 and 600,000 tons per year. Moreover, gasification, syngas purification, product synthesis, product separation and refining, as well as the utilization and treatment of \"three wastes\" all require \"integrated\" construction. Therefore, the investment in project construction often amounts to hundreds of millions or even billions of yuan. 　　Second, the supporting requirements are high, and it is difficult to enter this field due to the technical challenges. Modern coal chemical industry involves fields such as coal, electricity, and petrochemicals, and it places high demands on coal resources, water resources, the ecosystem, safety, the environment, as well as supporting social infrastructures such as transportation. Given the characteristics of coal in our country, coal chemical industry primarily uses bituminous coal, lignite, high-sulfur coal, and low-quality coal – materials that are abundant, widely available, and inexpensive. Advanced technologies in coal conversion and chemical synthesis are necessary to make use of these resources effectively. It is also important to develop and utilize coal resources scientifically in order to improve the efficiency of their processing and use. Therefore, the technical difficulty is relatively high. The key technologies of modern coal chemical industry still need further development and improvement; the demonstration plants for continuous pressurized gasification, coal-to-oil conversion, coal-to-olefins production, and coal-to-ethylene glycol have not yet achieved full technical and economic viability. 　　Third, pollution emissions are relatively concentrated, and the task of waste management is quite substantial. Due to its inherent properties, the processing and utilization of coal have a greater environmental impact than those of oil and natural gas; for example, converting each ton of coal typically generates 0.2 tons of waste residue, around 1.5 tons of carbon dioxide (CO2), and about 0.25 tons of wastewater. Modern coal chemical industries operate on a large scale, resulting in high and concentrated levels of pollutant emissions; therefore, they face significant environmental protection challenges. 　　Entering the 21st century, rising oil prices, shortages of petroleum raw materials, and high costs have led the chemical industry to develop a new understanding and interest in coal-based chemical processing. Coal-based chemical processing has entered a new phase of development, showing new trends: First, it will adopt a multi-product production model that relies on the C1 chemical industry chain to utilize coal for power generation, metallurgy, and chemical production ； 　　Secondly, international capital will **large-scale develop the coal chemical industry** in countries rich in coal resources, while the developed coal chemical industry focuses on technology development and strategic reserves ； 　　Thirdly, CO2 capture and storage will become an important issue in the development of coal chemical industry. Author: Ke Tizhu Source: \"China Petroleum and Chemical Economic Analysis\", Issue 12, 2011 Editor in charge: Guo Li